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Background: Cerebrospinal fluid (CSF) flow in disease has been investigated with two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI) in humans. Despite similar diseases occurring in dogs, PC-MRI is not routinely performed and CSF flow and its association with diseases is poorly understood. Objectives: To adapt 2D and four-dimensional (4D) PC-MRI to dogs and to apply them in a group of neurologically healthy dogs. Animals: Six adult Beagle dogs of a research colony. Methods: Prospective, experimental study. Sequences were first optimized on a phantom mimicking small CSF spaces and low velocity flow. Then, 4D PC-MRI and 2D PC-MRI at the level of the mesencephalic aqueduct, foramen magnum (FM), and cervical spine were performed. Results: CSF displayed a bidirectional flow pattern on 2D PC-MRI at each location. Mean peak velocity (and range) in cm/s was 0.92 (0.51-2.08) within the mesencephalic aqueduct, 1.84 (0.89-2.73) and 1.17 (0.75-1.8) in the ventral and dorsal subarachnoid space (SAS) at the FM, and 2.03 (range 1.1-3.0) and 1.27 (range 0.96-1.82) within the ventral and dorsal SAS of the cervical spine. With 4D PC-MRI, flow velocities of >3 cm/s were visualized in the phantom, but no flow data were obtained in dogs. Conclusion: Peak flow velocities were measured with 2D PC-MRI at all 3 locations and slower velocities were recorded in healthy Beagle dogs compared to humans. These values serve as baseline for future applications. The current technical settings did not allow measurement of CSF flow in Beagle dogs by 4D PC-MRI.

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Low-grade glioma patients have relatively long life expectancy for gliomas, but once they recur in malign, their prognosis can be poor. We analyzed factors corresponding to malignant recurrence by uni-and multi-variate analysis applying their treatment backgrounds. SUBJECTS: 261 newly diagnosed WHO grade 2 adults gliomas in 2004 to 2014. Malignant recurrence was determined by pathological diagnosis if the patient had a surgery (69% of the recurrent patients), otherwise contrast T1WI or 11C-methionine PET images if the patient was unable to undergo any surgery or biopsy. RESULTS: Age average 41 years old, the 10-year survival rate in all patients was 75%, and the mean of progression-free survival time was 7.8 years. Relapse event occurred in 115 cases (44%), and 67 % of them developed malignant glioma sometime. The 10-year survival rate for the patients who relapsed in malign was 37%, on the contrary, the patients who had recurrence but staying in low grade was 71% (p=0.0389). When they were categorized by 1p19q deletion and IDH1 mutation status, IDH wild type diffuse astrocytoma patients had significantly developed malignant glioma compared to oligodendroglioma and IDH mutant type diffuse astrocytoma (p<0.0001). The factors related to malignant progression were extracted as; recurrence in 2 years, 6% and over in MIB-1 index, no intervention longer than 18 months since the disease revealed, 1p19q non-co-deletion, less than 90% of tumor resection rate, and IDH wild type. In the 1p19q non-deletion patients, who were provisionally defined as diffuse astrocytoma patients here, the factors were resection rate, MIB-1 index, and duration between discovered the disease and the first surgery, but not the IDH mutant status (p＜0.0001, p=0.0015, p=0.0478 respectively). CONCLUSION: Recurrence in malign form low-grade glioma can be avoided by early intervention in 18 months from diagnosis and resection over 90% of volume of the tumor.

OBJECTIVE To describe perfusion and diffusion characteristics of the liver, spleen, and kidneys of healthy adult male cats as determined by morphological, perfusion-weighted, and diffusion-weighted MRI. ANIMALS 12 healthy adult male cats. PROCEDURES Each cat was anesthetized. Morphological, perfusion-weighted, and diffusion-weighted MRI of the cranial aspect of the abdomen was performed. A region of interest (ROI) was established on MRI images for each of the following structures: liver, spleen, cortex and medulla of both kidneys, and skeletal muscle. Signal intensity was determined, and a time-intensity curve was generated for each ROI. The apparent diffusion coefficient (ADC) was calculated for the hepatic and splenic parenchyma and kidneys on diffusion-weighted MRI images. The normalized ADC for the liver was calculated as the ratio of the ADC for the hepatic parenchyma to the ADC for the splenic parenchyma. RESULTS Perfusion-weighted MRI variables differed among the 5 ROIs. Median ADC of the hepatic parenchyma was 1.38 × 10−3 mm2/s, and mean ± SD normalized ADC for the liver was 1.86 ± 0.18. Median ADC of the renal cortex and renal medulla was 1.65 × 10−3 mm2/s and 1.93 × 10−3 mm2/s, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results provided preliminary baseline information about the diffusion and perfusion characteristics of structures in the cranial aspect of the abdomen of healthy adult male cats. Additional studies of cats of different sex and age groups as well as with and without cranial abdominal pathological conditions are necessary to validate and refine these findings.

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